Distribution Of Benthic Invertebrates Research Articles

Factors affecting the distribution of benthic macrofauna in estuaries contaminated by urban runoff

Contaminants derived from urban runoff have been shown to accumulate in estuarine sediments, reaching concentrations potentially capable of causing biological effects. Demonstration of effects, however, is difficult due to strong natural environmental gradients and the effects of past or present point-sources of contamination. We used multivariate methods to test two hypotheses relating to the effects of urban-derived contaminants on estuarine benthic communities. First, that patterns of distribution and abundance of benthic invertebrates in two urbanised estuaries would be different from those in two non-urbanised estuaries. Second, that the distributions of benthic invertebrates within and among the four estuaries would be related to those of urban-derived contaminants. Concentrations of contaminants were larger in estuaries with urbanised catchments and concentrations of Cu, Pb, Zn and DDT in some samples exceeded those at which biological effects may be expected to appear. Tests of differences in composition of benthic communities among estuaries showed that the two urban estuaries were not significantly different, but that they differed from both rural estuaries, which also differed from each other. Distributions of benthic invertebrates were significantly related to those of environmental variables, and were ordinated along axes that correlated with both natural environmental variables (nature of the sediment, position in estuary) and contaminants. Differences in faunas between the urban and non-urban estuaries were not, however, clear-cut and nor were relationships between faunal assemblages and environmental variables (including contaminants) consistent between two times of sampling.

Analysis of particulate organic matter retention by benthic structural elements in a lowland river (River Spree, Germany)

In a 6th-order section of the lowland River Spree, we analysed the retention of particulate organic matter (POM) by the following characteristic benthic structural elements: stable sands colonised by macrophytes or mussels, shallow sandy banks, and shifting sands. Our hypothesis was that the retention and storage of suspended particles and, therefore, the organic matter budget of a specific river reach is determined by the retentive properties of the various types of benthic structural elements in the channel. The relative storage capacity of each structural element for POM, chlorophyll-a, and protein was calculated. This storage capacity reflects the dynamics of processes that occur on the time scale of several months. Additionally, the relative trapping efficiencies of the structural elements were determined by means of tracer particles, which provide information about their retentive properties on shorter time scales. The investigated structural elements differed significantly with respect to the amount and composition of stored POM, and the time scale of retention. Biotic structures were the most effective retention features on longer time scales in the investigated lowland river. Macrophyte stands showed the highest relative storage capacity for organic matter, followed by stable sands that were colonised by mussels. On a shorter time scale during low discharge conditions, shallow sandy banks were similarly retentive. Shifting sands were least retentive, but the highest nutritional quality of the organic matter was found there. Those spatial patterns within a river reach are supposed to be an important factor controlling the microbial processing of POM in the benthic zone and the distribution of benthic invertebrates. Based on our results, it can be expected that changes in the size and composition of benthic structural elements within the channel (e.g. due to bank reinforcements, straightening measures, or impoundments) will influence the organic matter budget of a stream ecosystem considerably.

Composition, Abundance and Stratification of Macrobenthos in the Marine Area Impacted by Tar Aggregates Derived from the Haven Oil Spill (Ligurian Sea, Italy)

The impact of tar aggregates deriving from the Haven oil spill that occurred in 1991 on the soft-bottom macrobenthos off Arenzano (Ligurian Sea, NW Mediterranean; Italy) was investigated in this study. Core samples were collected to evaluate the composition, abundance and stratification of macrobenthos in three contaminated and three control sites. The distribution of tar aggregates (often settled by hydroids, bryozoans and serpulids) in the impacted area did not show distinct patterns related to sediment depth. The macrobenthos was numerically dominated by polychaetes, followed by crustaceans (amphipods, isopods and tanaids) and sipunculids, whereas bivalve molluscs were less represented. Ophiuroids and nemerteans were only occasionally found. Stratification was the main factor explaining the distribution of benthic invertebrates, highest abundances being observed in the upper 5 cm of sediment, while densities of individuals declined sharply in deeper sediment layers. No significant differences were observed in the abundance of both the whole benthic assemblage and of the main benthic taxonomic groups between contaminated and control sites. The higher abundance of sipunculids at the contaminated sites, instead, was attributed to the availability of empty tubes of polychaetes in which they take refuge. The polychaetes/amphipods ratios did not show strong differences between impacted and control sites. Multivariate analysis (MDS) showed a wide scattering among deep bottom samples and a comparatively high similarity among intermediate and superficial layers, regardless of the contamination level. In conclusion, the results reported here suggest that tar aggregates do not determine appreciable detrimental effects on the soft-bottom macrobenthos, which appeared to have recovered towards natural pristine conditions.

Long-term effects of local disturbance history on mobile stream invertebrates.

The patchy distribution of benthic invertebrates in streams and rivers is an important and widely researched phenomenon. Previous studies on reasons for this patchiness have neglected the potential role of local disturbance history, probably because most lotic invertebrates are mobile and any effect of disturbance history was thought to be short-lived. Here we demonstrate for a New Zealand gravel-bed stream that local disturbance history can have long-term effects on the distribution of highly mobile stream invertebrates. Buried scour chains (100 at each of three 20-m sites within a 350-m reach) indicated that a spate with a return period of 5 months caused a mosaic of bed patches with different stabilities. More than 2 months after the spate, we took random, quantitative samples at each site from five patches that had experienced 4 cm or more of scour during the spate, from five patches with 4 cm or more of fill, and from five stable patches. Density of the dominant invertebrate taxon, the highly mobile mayfly Deleatidium spp., and densities of another three of the seven most common taxa differed significantly between patch stability categories. Larvae of Deleatidium, the black fly Austrosimulium spp. and the dipteran Eriopterini were most abundant in fill patches, whereas Isopoda were most abundant in scour patches. Total invertebrate densities and densities of six common taxa also differed between sites, although these were only 95-120 m apart. These results show that local disturbance history can have long-term effects on lotic invertebrates and be an important cause of invertebrate patchiness. The observed effects might have been even stronger had we sampled sooner after the spate or after a large flood. Disturbance history may influence invertebrates both directly (through dislodgement or mortality) and indirectly, through effects on the spatial distribution of their resources. Our results suggest that the role of disturbance in structuring animal communities dominated by mobile species may be more important than previously thought.

The distribution of benthic invertebrates along the Austrian stretch of the River Danube and its relevance as an indicator of zoogeographical and water quality patterns - Part 2

The distribution of benthic invertebrates along the Austrian stretch of the River Danube and its relevance as an indicator of zoogeographical and water quality patterns - Part 2

Distribution of benthic invertebrates in relation to environmental factors. A study of European remote alpine lake ecosystems

Distribution of benthic invertebrates in relation to environmental factors. A study of European remote alpine lake ecosystems

Distribution of Benthic Invertebrates in Relation to Zonal Structure of Algal Communities in a Rocky Sublittoral Area, Tomari-hama, Oshika Peninsula, Northern Japan

Distribution of Benthic Invertebrates in Relation to Zonal Structure of Algal Communities in a Rocky Sublittoral Area, Tomari-hama, Oshika Peninsula, Northern Japan

Role of settlement in determining the distribution and abundance of barnacles in a temperate mangrove forest

Abstract An increased understanding of the role of early life history stages in determining the distributions of benthic invertebrates require studies covering a wide range of habitats, and preferably multiple scales. For one of the more prominent invertebrate groups, intertidal barnacles, much of our existing knowledge is drawn from studies of rocky shores, with few studies from other habitats. Here, we describe the distribution of adults of the temperate barnacle Elminius covertus in mangrove ( Avicennia marina ) forests of southeastern Australia. We sampled E. covertus on pneumatophores over a large-scale (50–100 m) across the forests from the landward to seaward edges. We also described large scale patterns along the shore (also a scale of 100 m). At the seaward edge of the forest, on a small spatial scale, the vertical distribution of E. covertus on pneumatophores over 15 cm was also investigated. Settlement and recruitment were also estimated by allowing barnacles to settle on artificial substrata. The processes influencing the patterns of adults of E. covertus were very different over the two major scales in this study. At the large-scale, adult Elminius covertus were abundant at the seaward edges of forests, declining through the forest, and were absent at the landward sections of forests. Recruitment, measured over 1 month, and 1 week, matched this pattern, and settlement, measured over a single high tide, also matched the adult distributions. Along the shore, differences in abundance of adult barnacles were matched by variation in settlement and recruitment. Post-settlement mortality had little influence on this pattern. In contrast, on the small, vertical scale, barnacles were most abundant on the upper 5 cm of pneumatophores, and least common near the substratum. This vertical pattern reflected the pattern of recruitment after 1 month. Settlement, however, was different, with more settlement on the 5 cm of pneumatophores closest to the substratum. The distribution of recruits after 1 week was intermediate between settlement and recruitment after 1 month. The vertical pattern of adults is therefore determined by post-settlement mortality occurring during the first month after settlement.

Benthic invertebrate distributions in the San Joaquin River, California, in relation to physical and chemical factors

The invertebrate fauna of nontidal portions of the lower San Joaquin River and its major tributaries is described in relation to water quality and habitat using canonical correspondence analysis, autecological metrics, and indicator species analysis. A large-scale (basin-wide) pattern in community response to salinity (sulfate-bicarbonate type) was detected when standardized, stable substratum was sampled. Community structure, taxa richness, and EPT (ephemeropterans, plecopterans, and trichopterans) richness varied with dissolved solids concentration (55-1700 mg total dissolved solids ·L-1), and distributions of many taxa indicated salinity optima. Distinct assemblages associated with either high or low salinity were evident over this range. Large-scale patterns in community structure were unrelated to pesticide distributions. Structure and taxa richness of invertebrate assemblages in sand substratum varied both with salinity and with microhabitat heterogeneity. The benthic fauna generally was dominated by a taxa-poor assemblage of specialized psammophilous species, contributing to a weaker relationship between community structure and water quality than was observed using standardized substratum. Habitat types and associated dominant species were characterized using indicator species analysis. Species assemblages did not vary substantially with irrigation regime or river discharge, indicating that structure of invertebrate communities was a conservative measure of water quality.

Assessing Sediments from Upper Mississippi River Navigational Pools Using a Benthic Invertebrate Community Evaluation and the Sediment Quality Triad Approach

Benthic invertebrate samples were collected from 23 pools in the Upper Mississippi River (UMR) and from one station in the Saint Croix River (SCR) as part of a study to assess the effects of the extensive flooding of 1993 on sediment contamination in the UMR system. Sediment contaminants of concern included both organic and inorganic compounds. Oligochaetes and chironomids constituted over 80% of the total abundance in samples from 14 of 23 pools in the UMR and SCR samples. Fingernail clams comprised a large portion of the community in three of 23 UMR pools and exceeded abundances of 1,000/m2 in five of 23 pools. Total abundance ranged from 250/m2 in samples from pool 1 to 22,389/m2 in samples from pool 19. Abundance values are comparable with levels previously reported in the literature for the UMR. Overall frequency of chironomid mouthpart deformities was 3% (range 0-13%), which is comparable to reported incidence of deformities in uncontaminated sediments previously evaluated. Sediment contamination was generally low in the UMR pools and the SCR site. Correlations between benthic measures and sediment chemistry and other abiotic parameters exhibited few significant or strong correlations. The sediment quality triad (Triad) approach was used to evaluate data from laboratory toxicity tests, sediment chemistry, and benthic community analyses; it showed that 88% of the samples were not scored as impacted based on sediment toxicity, chemistry, and benthic measures. Benthic invertebrate distributions and community structure within the UMR in the samples evaluated in the present study were most likely controlled by factors independent of contaminant concentrations in the sediments.

Benthic invertebrate distributions in the San Joaquin River, California, in relation to physical and chemical factors

Benthic invertebrate distributions in the San Joaquin River, California, in relation to physical and chemical factors

DISTRIBUTION OF BENTHIC INVERTEBRATES IN RELATION TO STREAM FLOW CHARACTERISTICS IN A NORWEGIAN RIVER

The distribution of benthic invertebrates was studied under different flow regimes in an unregulated West Norwegian river. A total of 150 quantitative benthic samples was taken from fixed transects at three different stations in the river. Hydrophysical characteristics were recorded at each sampling spot. The depth and flow preferences of the different species varied. According to the distribution, two of the species, the caddisflies Polycentropus flavomaculatus and Oxyethira spp., were closely associated with shallow, slow-flowing areas, differing significantly from nearly all the other species tested. Rhyacophila nubila, Baetis rhodani and Glossosoma intermedia were all classified as rheophilic, not differing significantly in preferences of water velocity and depth. Diura nanseni was most abundant in water velocities above 30 cm s−1. This species preferred shallow areas, in contrast with Leuctra hippopus and G. intermedia. Three of the species, Amphinemura sulcicollis, A. borealis and L. hippopus were classified as indifferent with respect to water velocities. Gaussian logit and linear logit regression showed that only one of the species tested, A. borealis, had a significant response curve to the depth of the water column. The density of this species decreased sigmoidally with an increase in depth. D. nanseni was the only species showing a significant response to the water velocity.

Distribution of benthic invertebrates at different depths in a shallow reservoir in the KwaZulu-Natal Midlands

The bottom of a freshwater reservoir in the KwaZulu-Natal Midlands was sampled for macro-invertebrates and macrophytes at depths of 0.5 m, 1 m, 2 m, and 3 m. The water plants Elodea spp. which did not occur much beyond 1 m appeared to be a major deter-minant for the presence of invertebrates. At 2 m and 3 m, when temperature and light decreased greatly, it was replaced by the algae Chara spp. Over 98 of the macroinvertebrate individuals in 21 species and 14 families occurred in water 1 m or less in depth. At 2 m and deeper, there was a rapid decline of species, with only one, a snail, occurring at 3 m. Odonata species occurred only in water 1 m or less in depth. Among the Ephemeroptera, Caenis sp. was abundant at 0.5 m and the most dominant species of all. At 1 m, the most dominant species was Cleon palidulosum of the Baetidae. Both in terms of food for waterfowl and trout, and as a reserve for aquatic macroin vertebrates, the shallow fringe of the reservoir was playing by far the major role compared with the deeper, open water. It is recommended both for biotic conservation and fishing that reservoirs have a shallow rim and constant water levels.

The distribution of benthic invertebrates along the Austrian stretch of the River Danube and its relevance as an indicator of zoogeographical and water quality patterns - part 1.

A total of 1289 invertebrate species is now known along the Austrian stretch of the River Danube. These species characterize the free-flowing section of the river as a transition zone of the hyporhithron/epipotamon. Most species of the Austrian Danube have individual saprobic values between 1.6 and 2.8 on average characterizing a beta-mesosaprobic zone. When different family-based indices and scores were converted into saprobic water quality classes, samples with the same data-base (set of species and their absolute abundance) differed between classes I and III. These deviations from the proven water quality class II can be explained 1. by different environmental conditions, such as the relationship between species abundance and hydrological variables rather than from real differences in water quality, 2. from calculations on higher taxonomic levels. In principal, the deviations of ASPT estimates from the real saprobic water quality situation in Austrian rivers are of little use in making management decisions.

Hydraulic parameters and benthic invertebrate distributions in two gravel‐bed New Zealand rivers

SUMMARY1. Benthic invertebrates were sampled over a matrix of about eighty combinations of mean velocity (10–150cms−1) and depth (10–150cm) in two rivers that differed in substrate size variability. Vertical velocity profiles were measured at each sample site and substratum roughness was measured and estimated from percentage cover by stone size classes. The influence of depth on periphyton biomass was also measured.2. The hydraulic and substrate data were used to investigate the correlations between conventional (mean velocity, depth, substrate size) and complex hydraulic variables (Froude number, shear velocity, and water column and boundary Reynolds number) that were either calculated from direct measurements or inferred from mean velocity, depth, kinematic viscosity and substrate roughness. The ecological relevance of these hydraulic variables was investigated by comparing their degree of correlation with invertebrate densities and community metrics.3. The invertebrate variables had similar correlations with mean velocity and the complex near‐bed hydraulic variables in the river with uniform cobble substrates. In the river with diverse substrates, however, average correlations with Froude number, and inferred shear velocity and boundary Reynolds number were 25–45% higher than with velocity. Of all the individual hydraulic parameters, the boundary Reynolds number, calculated from simple measures, was most strongly correlated with benthic invertebrate distributions and taxa richness. However, invertebrate distributions were more strongly correlated with predictions of multiple regression models, incorporating substrate size, depth and mean velocity, than with any single hydraulic variable.4. Hydraulic influences on food availability and oxygen concentration in the benthos are likely mechanisms affecting the hydraulic preferences of several taxa. Lower periphyton biomass with depth, partly attributable to light attenuation, appeared to have a non‐hydraulic influence on a collector‐browser species.

Preliminary results of a nitrogen freeze-coring methodology for determining the vertical distribution of benthic invertebrates from the lowland River Babingley, UK

A Nitrogen freeze-coring method was used to sample the benthic invertebrate fauna of the river Babingley, UK to a depth of 70 cm. The fauna was stunned in situ using 700 V, 50 Hz AC prior to the re...

The vertical distribution of benthic invertebrates in the bed of the Thomson River, Victoria, Australia

(1991). The vertical distribution of benthic invertebrates in the bed of the Thomson River, Victoria, Australia. SIL Proceedings, 1922-2010: Vol. 24, No. 3, pp. 2060-2060.

The distribution of benthic invertebrates along a natural turbidity gradient in Lake Temiskaming, Ontario-Quebec

Lake Temiskaming, a rift valley lake on the Ontario-Quebec border, exhibits a permanent gradient of turbidity due to tributary streams which cut through clay deposits to the north of the lake. Concentrations of total phosphorus (TP) also decreased from north to south, with values suggesting mesotrophic conditions. Concentrations of chlorophyll a were characteristic of oligotrophic lakes and showed little relationship to either turbidity or TP. Large numbers of Tubificidae were found at our northernmost sampling station at a depth of 50 m, probably reflecting the localized impact of allochthonous organic matter introduced by a tributary stream. Numerical abundance of the benthic fauna was much lower and did not vary significantly among the six more southerly 50 m stations, but biomass declined from north to south as Heterotrissocladius oliveri relaced Pontoporeia hoyi. Numerical abundance did not differ significantly among stations at depths of 10 m, but biomass decreased from north to south reflecting the distributions of the largest species, Hexagenia sp. and P. hoyi. Intensive sampling on two transects showed that maximum numbers of invertebrates occurred in the profundal zone. While these results are consistent with the correlation between TP and zoobenthic biomass reported by other investigators, size selective predation by fish may also be important in controlling the distribution of benthic invertebrates in Lake Temiskaming.

Impacts of wetland afforestation on the distribution of benthic invertebrates in acid streams of Westland, New Zealand

Abstract Inter‐relationships between some physical and chemical parameters of streams, the degree of catchment development, and benthic invertebrate distributions were investigated on two dates at 26 running‐water sites in North Westland, New Zealand. Streams draining catchments recently developed for forestry had higher summer water temperatures, greater total reactive aluminium concentrations (up to 31°C and 911 mg m‐3, respectively), and lower pH (down to 4.1) than most streams draining undeveloped wetland or native‐forested catchments. Apparent differences in water chemistry were attributed to the most recent development being at the heads of wetland catchments where leaching of organic acids into drainage waters was probably highest, rather than to any effects of development per se. Overall, streams that were very acidic (pH mostly < 5.0 and often < 4.5) and drained wetland catchments supported 1.3–3.3 fewer invertebrate taxa than sites that consistently had pH>4.5 and drained native‐forested catchments. Invertebrate colonisation appears to be limited by the extremeacidity of brownwater streams on pakihi wetlands.

Vertical distribution of Benthic Invertebrates in the Bed of the Thomson River, Victoria

The vertical distribution of the benthic fauna was studied at three sites on the Thomson River using a freeze-corer. Samples were taken over two years in early and late summer. At each site an average of 72 to 84% of the fauna was found in the 0-10 cm zone of the riverbed, 10-20% in the 10-20 cm zone and 6-8% in the 20-30 cm zone; flooding at one site was followed by an increase in the depth to which the fauna penetrated. Surface percentage abundances were probably underestimated because of the inability of the corer to sample surface rocks and their fauna consistently and because the coring operation disturbs the surface fauna to some extent before it can be frozen. Nevertheless, the results indicate that in the Thomson River the majority of the fauna is within the depth range (0-10 cm) of a Surber sampler.